94 jetta oil pressure problems

yeah so my 94 jetta had the oil light on blinkin and dingin oil level was fine so i thought it might be a sensore to to be shore i replaced both of them...to no avail the light and buzzer was still goin off so i thought it could be the oil pump so i changed it ...but the light and buzzer is still isnt goin off..... it idles fine then when i get to about 2500 rpm thats when itr comes on and dings what the heck :banghead:....any suggestiond to what else i could do would be greatly appreciated